Ever since I PCS'ed I haven't found any local shops that carry it. My M4 patterns well enough with Winchester 2 3/4" buckshot but I would like to finds some more Federal to keep on hand.

http://www.targetsportsusa.com/federal-le-tactical-ammo-12-gauge-2-34-00-buckshot-9-pellets-le13200-p-3082.aspx

SG Ammo has it in the low recoil variety, too. Lots of online retailers stock it.

SGAmmo

I bought the low recoil version at SG Ammo.

Hornady is a viable alternative if you cant find the federal.  It uses the same wad technology and patterns well in my shotguns.

Hornady loads there 00 buck way faster than federal, they don't come close to the same patterens as federal LE loads at least from my shotguns, Hornady's @ 1600fps will set your teeth back.

I've used some of the low recoil 00 buck that works almost as well as the Federal in my 590A1.

http://www.hornadyle.com/products/shotgun/tap-reduced-recoil/tap-reduced-recoil

The 8 pellet Hornady VersaTite wad buckshot at 1600 fps patterns almost as good, but not quite, as the Federal Premium full power 9 pellet FliteControl in my testing.  I want that extra pellet. Both of these full power loads have stout recoil.  You never notice recoil under stress, however. For home defense, either load will put all pellets into a fist sized target at 15 yards.  The FliteControl will put all 9 in 3-4" at 15 yards, and all 9 in a 10-11" circle at 50 yards.  I have posted targets here demonstrating this.  The FliteControl wad is a little deeper than the  VersaTite wad, which may account for its slightly tighter pattern.



FliteControl in red.  VersaTite in white.